<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>beforeUpdate和updated钩子函数的使用</title>
</head>
<body>
    <script src="../js/vue.js"></script>
    <div id="app">
        <div v-if="isShow" ref="self">
            test
        </div>
        <button @click="isShow=!isShow">更新</button>
    </div>
     
    <script>
        let app = new Vue({
          el:"#app",  
          data: { 
            isShow:false 
        },
        beforeUpdate(){
            console.log('更新之前')
            console.log(this.$refs.self)
        },
        updated(){
            console.log('更新之后')
            console.log(this.$refs.self)
        } 
    }) 
    </script>
</body>
</html>